1. Field of the Invention
This invention pertains generally to selective visual display systems, and particularly to display peripheral input devices of the joystick or pointing stick type. These devices find primary application with computer operators to control the position of a pointer or cursor on a computer display, though other applications combining keys and navigational control are well known and contemplated by the present inventors. For the purposes of this disclosure, a key will be defined herein as xe2x80x9ca button or lever that is pressed with the finger to operate a machine.xe2x80x9d The machine may be selected from many types of devices, including remote controls for televisions, sound systems and other similar devices, computers and computer displays, appliances, airplanes (both radio controlled and otherwise), large and small machinery, land vehicles, and many other diverse devices too numerous to mention.
2. Description of the Related Art
Computing and calculating tools have existed in various form for thousands of years, dating back to devices such as the abacus. These tools simplified basic tasks, thereby saving time and allowing humans to direct their efforts to other important activities. With the advent of electronic circuits and systems came the development of general purpose computers, which could be used for more than one function. Through special programming, computers could be used to emulate or model other devices and systems, allowing the computer to be applied to diverse and complicated tasks. Many early general purpose computers depended upon punched cards or paper tapes for input of instructions, and, after performing necessary computation, printed output onto paper. This is referred to as batch processing. As might be expected, the instruction set would often be inadequate, and so an operator would be required to replace or add necessary instructions by replacing the punched cards. Needless to say, the computers were not well suited for performing instructions and operations in real time. Furthermore, the computers required large space and enormous electric power, frequently requiring entire rooms and special air-conditioning systems.
As microelectronics progressed, general purpose computers continued to become capable of more and more diverse tasks. Typewriter-style keyboards and other input devices replaced punched cards, and television-style video displays and electronic output complimented paper print-outs. Numerous further developments eventually led to the current interactive video display. Pictorial symbols, commonly known as icons and buttons, provide visual as well as textual identification of functions available to the computer user.
Through a navigational control, the user may simply move about the display and select from the icons and buttons. With improved user interface and enhanced capability, computers are now widely used. These computers, more powerful than the greatest super computers of only a few decades ago, are commonly referred to as personal computers or PC""s. The enormous computational capability has led to applications for personal computers extending to areas well beyond the initial accounting and typewriter functions, and new applications are continuously being developed.
With the new applications and interactive video display has come a desire for better ways to provide input to the computer. While the keyboard continues to dominate as the best method for textual input, navigational functions including cursor position control are now primarily being performed with input devices such as a mouse, trackball, touch pad, joystick or pointing stick. These devices indicate the user""s desire for cursor movement more naturally to the computer than a keyboard can. For example, the movement of a trackball or mouse in one direction, which may be at any angle on a planar surface from zero through 360 degrees, can be precisely translated to the computer. Furthermore, the amount of movement desired is also readily communicated by the relative rate of movement of the mouse or trackball. These desires are communicated from a relatively small device, most frequently smaller than a human hand.
Unfortunately, with a mouse, joystick or many trackballs the user must first remove one hand from the keyboard. Since, as aforementioned, the keyboard is still the primary source for textual input, the removal of one hand therefrom is most undesirable. Rapid placement of the hand upon a keyboard is nearly impossible, and nearly all computer users have experienced the frustration of incorrectly placing one or both hands on the keyboard and mistakenly typing incorrect keys. Furthermore, the mouse in particular requires a relatively large flat surface upon which to travel, which is often unavailable on crowded desktops or when the PC is a portable, notebook type computer.
In recognition of these and other drawbacks of the prior art, a number of devices have been modified or designed. Trackballs have been designed with much smaller dimension, as have touch pads. Unfortunately, neither of these devices is small enough to fit within the existing, already crowded typewriter style keyboard. When a mouse is unsuitable, the pointing stick is presently the most widely accepted device for navigational control. The pointing stick is a small stick, which protrudes vertically out from a keyboard, frequently between keys. The pointing stick incorporates several small sensors, frequently of the strain-gauge type, which sense applied force and direction with very little or no actual movement of the stick. Because the pointing stick is force-sensitive, rather than sensitive to actual movement, very little space is required. As already noted, that means that the pointing stick may be included within a keyboard. Furthermore, the pointing stick may be designed to be sensitive to force along all three spatial axes, rather than the two axes available to a mouse or trackball.
Placement of the pointing stick is frequently in the lower central region of a keyboard. This placement is arrived at out of convenience, allowing a user to control the pointing stick with either the left or right pointer finger. Presently, these pointing sticks are manufactured separately from the balance of the keyboard, and placed within the keyboard during keyboard assembly. The pointing stick is electrically connected to a motherboard in the computer by a separate flexible cable.
The need for a separate cable assembly for the pointing stick and routing of the cable assembly not only adds to the cost of the finished computer, but complicates the assembly and makes the computer keyboard less compact.
In one manifestation, the invention provides a computer keyboard assembly that has a housing with several apertures through which keys pass. A flexible membrane is located adjacent the housing and has a first surface and a second surface. The flexible membrane has circuit lines on the first surface and an integral pointing stick cable. The circuit lines extend onto the pointing stick cable from the flexible membrane. The keys are electrically connected to the circuit lines on the first surface. A backing plate is structurally supporting the membrane. The membrane is located between the backing plate and the housing. A pointing module is attached to the backing plate. The pointing module is electrically connected to the pointing stick cable such that electrical signals from the pointing module are conducted to the circuit lines on the pointing stick cable. The pointing stick cable wraps around a side of the backing plate. The pointing module has a shaft that extends through an aperture in the backing plate and membrane and the shaft extends above the keys. The flexible film has a motherboard cable and an input button cable.